Staircase.



v T. BEEVERS.

STAIRGASB.

APPLICATION FILED 111:0. 29, 1908.

996,903, Patented July 4, 1911.

COLUMBIA PLANOGRAPH c0., WASHINGTON. D. c.

in ex ES ATT FTQ.

THOMAS BEEVERS, OF LONDON, ENGLAND, ASSIGNOB TO THE SAFETY TREAD SYNDIGATE LIMITED, OF LONDON, ENGLAND, A CORPORATION OF GREAT BRITAIN.

STAIRCASE.

Specification of Letters Patent.

Patented July 4, 1911.

Application filed December 29, 1908. Serial No. 469,856.

To all whom it may concern:

Be it known that I, THOMAS Bnnvnns, a subject of the King of GreatBritain, and resident of 15 Barbican, in the city of London, England,civil engineer, have invented new and useful Improvements Relating toStaircases, of which the following is a specification.

The present invention relates to treads for stair-cases and the like andhas for its ob ject to cheapen the construction thereof.

According to this invent-ion, the treads comprise slabs of concrete orother similar material, in combination with metallic grids composed oftroughs and cross ties so disposed that the troughs form metal linedgrooves on the surface of the treads, while the cross ties formreinforcements embedded in the body of the slabs.

In the accompanying drawing, Figure 1 shows in sectionalelevation, afragment of a stair-case employing treads embodying this invention. Fig.2 is a sectional elevation of a modified form showing the improved treadapplied for the purpose of repairing existing steps. Fig. 3 is a planview of a modified grid-like structure before it is embedded in theconcrete. Fig. 4 is a cross section of the same, and Fig. 5 is alongitudinal section through the tread and support.

Referring to Figs. 1 and 2, a is a tread consisting of a concrete slabreinforced with a grid-like structure of U-shaped metal troughs btransversely strung together by bars 0 which are threaded through a rib(Z depending from the bottoms of said troughs.

The U-shaped metal troughs b are exposed at their upper surface, forminga series of open troughs in the upper surface of the tread, butotherwise the troughs and the bars 0 which string them together, arecompletely embedded in the concrete.

The risers are denoted by g, and consist of metal plates which, inbuilding a staircase, have their ends embedded in the structure of thebuilding. These risers are preferably provided with nosings h andsupporting lugs 2', j. The supporting lugs project, the one backward andthe other forward, and act as supports for the treads which are moldedof such a size that they will lie snugly thereon and can be secured by alittle grouting of cement applied at the back of the nosings which arecarried by the risers.

Before the concrete treads are fitted, temporary treads may be laid inposition so as to save the use of tiles to protect the permanent treadswhile the building is in progress. After the building is complete, thepermanent treads may be fitted and secured without difi'iculty.

For repairing the surface of existing steps, the tread need not be sothick but it will generally be desirable to furnsh a metal front to takethe place of a nosing, such, for example, as the angle-iron Z, as shownin Fig. 2, to which the bars 0 may be secured.

Referring to Figs. 3 to 5, the U-shaped bars of the part of the treadare shown as of a slightly difierent configuration in cross section andare denoted by b. In this form, it is preferred to provide at the endsof the treads, channel irons m adapted to slide on to the ribs 12 of thesupports 0, which latter may be secured to the stringers of thestaircase in any suitable manner.

What I claim is:

A. tread composed of concrete and a grid like metal structure havinggrooved bars disposed in the concrete so as to expose metal lined opengrooves in the surface of the tread, the upper edges of the metal wallsof the grooves being exposed on the tread surface and a reinforcementinterlocked with the grooved bars and embedded within the body of thetread and extending transversely to the metal lined grooves,substantially as described. I

London, the 10th day of December, 1908.

THOMAS BEEVERS.

Signed in the presence of ALFRED S. BISHOP, P. A. NEWTON.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. C.

